profit = revenue - expenses
Filling in the given values, where n is the number of necklaces Sam must sell ...
... 1000 = 10n - (5n +5000)
... 6000 = 5n . . . . . . collect terms, add 5000
... 1200 = n . . . . . . . divide by 5
The appropriate choice is
... D. 1200
Explanation:
If 
then taking the reciprocal gives
L=12
W=x
A=168
A=L x W
168=12 x W
168\12=12w/12
W=168/12
W=14
